BOSTON — Lawyers for Boston Marathon bombing suspect Dzhokhar Tsarnaev asked a judge Wednesday to lift restrictions placed on him in prison, arguing that the conditions are overly harsh, have left him nearly totally isolated and are impairing their ability to defend him.

Tsarnaev's lawyers said in a motion filed in court that he has been confined to his cell except for visits from them and has "very limited access" to a small outdoor enclosure.